Mechanical Pump-Assisted Active Two-Phase Thermal Control System (MPA2PTCS) Transient Modeling

High-throughput satellite (HTS) provides much more data handling capability than the conventional fixed satellite service (FSS) which significantly reduces the operational cost for the service providers. In the meantime, the power consumption of the HTS payload electronics, and thus the required heat rejection capability (as high as 25 kW) has increased tremendously. For high heat load, high heat flux, and long transport distance applications, the passive two-phase and single-phase pump loop have reached their limits. Recent developments have shown that the MPA2PTCS has great potential in offering thermal management to the HTS market. Additionally, MPA2PTCS has better architecture flexibility and better tolerance to late-stage design change. Compared to the single-phase thermal control system, the MPA2PTCS offers better temperature uniformity, lower pumping power, and potentially lighter system mass. With these benefits, the prospect of deploying two-phase thermal control technology in high power spacecraft is very promising. The operation of MPA2PTCS is more complex than that of the single-phase flow loop. To conserve operating power for the satellite, the MPA2PTCS is in non-operational state until it reaches the service orbit. During this orbit transfer period, the MPA2PTCS temperature will drops to its lowest non-operating temperature. Once in orbit, the MPA2PTCS will commence its start-up procedures. Unlike the single-phase flow loop, the procedures and the responses of the MPA2PTCS during start-up is much more complex. Therefore, it is prudent to predict the MPA2PTCS behavior prior to its deployment to ensure its robust operation. This paper describes the transient start-up modeling and the behavior of the MPA2PTCS from its dormancy to the final steady state. The variables used in the modeling reflect the actual designed operating parameters. The modeling results will be compared to the MPA2PTCS acceptance test data in the near future.